Nitroglycerin

Why is this drug prescribed: Nitroglycerin is prescribed to prevent and treat angina pectoris (suffocating chest pain). This condition occurs when the coronary arteries become constricted and are not able to carry sufficient oxygen to the heart muscle. Nitroglycerin is thought to improve oxygen flow by relaxing the walls of arteries and veins, thus allowing them to dilate.
Nitroglycerin is used in different forms. As a patch or ointment, nitroglycerin may be applied to the skin. The patch and the ointment are for prevention of chest pain.
Swallowing nitroglycerin in capsule or tablet form also helps to prevent chest pain from occurring.
In the form of sublingual (held under the tongue) or buccal (held in the cheek) tablets, or in oral spray (sprayed on or under the tongue), nitroglycerin helps relieve chest pain that has already occurred. The spray can also prevent anginal pain. The type of nitroglycerin you use will depend on your condition.

Most important fact about this drug: Nitroglycerin may cause severe low blood pressure (possibly marked by dizziness or light-headedness), especially if you are in an upright position or have just gotten up from sitting or lying down. You may also find your heart rate slowing and your chest pain increasing. People taking diuretic medication, or who have low systolic blood pressure (less than 90 mm Hg) should use nitroglycerin with caution.

How should you take this medication: Since nitroglycerin is available in many forms, it is crucial for you to follow your doctor's directions for taking the type of nitroglycerin prescribed for you. Never interchange brands.
Ideally, you should take nitroglycerin while sitting down--especially if you feel dizzy or light-headed--so as to avoid a fall.
--If you miss a dose...
If you are using a skin patch or ointment:
Apply it as soon as you remember. If it is almost time for your regular dose, skip the one you missed and go back to your regular schedule. Never apply 2 skin patches at the same time.
If you are taking oral tablets or capsules:
Take the forgotten dose as soon as you remember. However, if it is within 2 hours of your next dose, skip the one you missed and go back to your regular schedule. Never take 2 doses at the same time.
--Storage instructions...
Keep this medication in the container it came in, tightly closed. Store it at room temperature. Do not refrigerate.
Avoid puncturing the spray container and keep it away from excess heat.
Do not open the container of sublingual tablets until you need a dose. Close the container tightly immediately after each use. Do not put other medications, a cotton plug, or anything else in the container. Keep the sublingual tablets handy at all times. Keep the patches in the protective pouches they come in until use.

What side effects may occur: Side effects cannot be anticipated. If any develop or change in intensity, inform your doctor as soon as possible. Only your doctor can determine if it is safe for you to continue taking nitroglycerin.
More common side effects may include:
Dizziness, flushed skin (neck and face), headache, light-headedness, worsened angina pain
Less common or rare side effects may include:
Diarrhea, fainting, heart pounding, low blood pressure, nausea, numbness, pallor, restlessness, severe allergic reactions, skin rashes and eruptions, sweating, vertigo, vomiting, weakness

Why should this drug not be prescribed: You should not be using nitroglycerin if you are allergic to it or to the adhesive in the patch, if you have a head injury, or if you have any condition caused by increased fluid pressure in your head. Nitroglycerin should not be taken if you have severe anemia or if you recently had a heart attack. The capsule form should not be used if you have closed-angle glaucoma (pressure in the eye) or suffer from postural hypotension (dizziness upon standing up). Do not take the tablets if you are using the impotence drug Viagra.

Special warnings about this medication: If your vision becomes blurry or your mouth becomes dry while taking nitroglycerin, it should be discontinued. Contact your doctor immediately if these symptoms develop.
You may develop acute headaches if you take nitroglycerin excessively. Also, some people may develop a tolerance to nitroglycerin, and it may become less beneficial over time, especially if used in excess.
Nitroglycerin tablets lose their effectiveness when exposed to air. If you are taking sublingual nitroglycerin, you may notice a burning or tingling sensation. This does not necessarily mean that tablets which have been exposed to air for a long period of time are still good.
Take no more than the smallest possible amount needed to relieve pain.
Daily headaches may be an indicator of the drug's activity. Do not change your dose to avoid the headache, because you may reduce the drug's effectiveness at the same time.
Before taking nitroglycerin, tell your doctor if you have had a recent heart attack, head injury, or stroke; or if you have anemia, glaucoma (pressure in the eye), or heart, kidney, liver, or thyroid disease.
If you use a patch, dispose of it carefully. There is enough drug left in a used patch to be harmful to children and pets.
Since nitroglycerin can cause dizziness, you should observe caution while driving, operating machinery, or performing other tasks that demand concentration.
The benefits of applying nitroglycerin to the skin of people experiencing heart attacks or congestive heart failure have not been established. If you are using the medication for these conditions, your doctor will monitor you to prevent low blood pressure and pounding heartbeat.

Possible food and drug interactions when taking this medication: If nitroglycerin is taken with certain other drugs, the effects of either could be increased, decreased, or altered.
Taken with many high blood pressure drugs, nitroglycerin may cause extreme low blood pressure (dizziness, fainting, numbness). Take particular care with calcium channel blockers such as Calan and Procardia XL, as well as isosorbide dinitrate (Sorbitrate, Isordil, others), isosorbide mononitrate (Ismo, others), blood vessel dilators such as Loniten, and beta-blocker medications such as Tenormin. Nitroglycerin may also cause a severe drop in blood pressure when taken with the impotence drug Viagra.
Aspirin can increase the effects of nitroglycerin.
Alcohol may interact with nitroglycerin and cause a swift decrease in blood pressure, possibly causing dizziness and fainting.
Also be alert for an interaction with dihydroergotamine (D.H.E.). Check with your doctor if you are uncertain about any combination you plan to take.

Special information if you are pregnant or breastfeeding: It has not been determined whether nitroglycerin might harm a fetus or a pregnant woman. As a result, nitroglycerin should be used only when the benefits of therapy clearly outweigh the potential risks to the fetus and woman. It is not known if nitroglycerin appears in breast milk; therefore, a nursing mother should use nitroglycerin only on advice of her doctor.

Recommended dosage: The following section is intended to provide guidelines for taking nitroglycerin. Follow your doctor's instructions carefully for using nitroglycerin in the form prescribed for you.
ADULTS:
Sublingual or Buccal Tablets
At the first sign of chest pain, 1 tablet should be dissolved under the tongue or inside the cheek. You may repeat the dose every 5 minutes until the pain is relieved. If your pain continues after you have taken 3 tablets in a 15-minute period, notify your doctor or seek medical attention immediately.
You may take sublingual or buccal nitroglycerin from 5 to 10 minutes before starting activities that may cause chest pain.
Patch Form
A patch is applied to the skin for 12 to 14 hours. After this time, the patch is removed; it is not applied again for 10 to 12 hours (a "patch-off" period). Apply the patch as soon as you remove it from its protective pouch.
Spray Form
At the first sign of chest pain, spray 1 or 2 pre-measured doses onto or under the tongue. You should not use more than 3 doses within a 15-minute period. If your chest pain continues, you should contact your doctor or seek medical attention immediately.
The spray can be used 5 to 10 minutes before activity that might precipitate an attack.
Ointment Form
Your initial dose may be a daily total of 1 inch of ointment. Apply one-half inch on rising in the morning, and the remaining one-half inch 6 hours later. If needed, follow your doctor's instructions for increasing your dosage. Apply in a thin, uniform layer, regardless of the amount of your dosage. There should be a daily period where no ointment is applied. Usually, the "ointment-off" period will last from 10 to 12 hours.
Absorption varies with site of application--more is absorbed through the chest.
Sustained-Release Capsules or Tablets
The smallest effective amount should be taken 2 or 3 times a day at 8- to 12-hour intervals.
CHILDREN:
The safety and effectiveness of nitroglycerin have not been established for children.
OLDER ADULTS:
In general, dosages less than the above adult dosages are recommended, since the elderly may be more susceptible to low blood pressure and headaches.